Mostly fix json schema generation for otel config. (#607)

* Mostly fix json schema generation for otel config.
This is such a big part of the config that it's worth having.
It's possible that the schema is a little too lenient, and would allow invalid config for custom attributes or headers, but mostly it is OK.

* CHANGELOG.md

* Fix Http exporter schema gen

* Fix failing test.
Add comment to say what a mirror enum is used for.

Co-authored-by: bryn <bryn@apollographql.com>

CHANGELOG.md

@@ -60,6 +60,15 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 use a layer vs a plugin. As the layer API is a subset of the plugin API the layer option has been removed.
 ## 🚀 Features
 ## 🐛 Fixes
+- **Reporting plugin schema generation** ([PR #607](https://github.com/apollographql/router/pull/607))
+  Previously our reporting plugin configuration did not participate in json schema generation. This is now broadly correct
+  and make writing schema much easier.
+
+  To generate a schema use the following command.
+  ```
+  router --schema > apollo_configuration_schema.json
+  ```
+  and follow the instructions for associating it with your particular text editor/IDE. 
 ## 🛠 Maintenance
 ## 📚 Documentation
 

apollo-router/src/configuration/mod.rs

@@ -274,7 +274,7 @@ pub(crate) fn default_service_namespace() -> String {
     "apollo".to_string()
 }
 
-#[derive(Debug, Clone, Deserialize, Serialize)]
+#[derive(Debug, Clone, Deserialize, Serialize, JsonSchema)]
 #[serde(deny_unknown_fields, rename_all = "snake_case")]
 pub enum Secret {
     Env(String),
@@ -292,7 +292,7 @@ impl Secret {
     }
 }
 
-#[derive(Debug, Clone, Default, Deserialize, Serialize)]
+#[derive(Debug, Clone, Default, Deserialize, Serialize, JsonSchema)]
 #[serde(deny_unknown_fields)]
 pub struct TlsConfig {
     domain_name: Option<String>,
@@ -331,6 +331,8 @@ mod tests {
     use super::*;
     use apollo_router_core::prelude::*;
     use apollo_router_core::SchemaError;
+    #[cfg(unix)]
+    #[cfg(any(feature = "otlp-grpc"))]
     use insta::assert_json_snapshot;
     use reqwest::Url;
     use schemars::gen::SchemaSettings;
@@ -346,6 +348,7 @@ mod tests {
     }
 
     #[cfg(unix)]
+    #[cfg(any(feature = "otlp-grpc"))]
     #[test]
     fn schema_generation() {
         let settings = SchemaSettings::draft2019_09().with(|s| {